Most cars require a relatively big engine to produce enough power to accelerate the car quickly. The gas engine on a conventional car is sized for the peak power requirement. In fact, most drivers use the peak power of their engines less than one percent of the time. The hybrid cars that use electric and engine power source are designed to overcome problem of engine sizing and enhance engine performance. These cars use a much smaller engine, one that is sized closer to the average power requirement than to the peak power. In a small engine, however, the efficiency can be improved by using smaller, lighter parts, by reducing the number of cylinders and by operating the engine closer to its maximum load.
However, this necessitates development of dedicated engine coupled with the electric motor and drive, transmission system. Further tailored transmission system is needed to run these vehicles. This has resulted in impediment of application of hybrid technology to existing or newly developing vehicle/engine driven systems. Further, it is always desirable to size and operate engine of any of the engine driven system in the range of average power requirement to enhance fuel efficiency. Thus, there is a need to provide power assisting system for engine drive systems/vehicles so as to provide flexibility of integrating such assisting system with the engines/vehicles to enhance engine/vehicle performance without the need of using dedicated drive system, engines etc.
Hybrid cars were conceptualized over a hundred years ago. First discussions of the hybrid cars date back to 1902. Piper from Belgium was the first one to file for a patent in the US on the subject of hybrid. His patent was granted 100 years ago. Although there were several attempts in the past, there is no reference found in the literature for a highly efficient, easy to retrofit, and cost effective hybrid design. With the current major fluctuations in the prices of crude oil, there is an upsurge in the interest of designing and building hybrid cars. However, their demand remains low due to high cost associated with it. Attempts are made to develop hybrid vehicle system. The prior art is mentioned hereunder. U.S. Pat. No. 6,367,570 discloses a hybrid electric vehicle with electric motor providing strategic power assist to load balance internal combustion engine. It comprises of internal combustion engine coupled to motor and control system.
U.S. Pat. No. 5,678,646 discloses a propulsion system for a vehicle comprising an electric motor, circuit breakers which switch field windings of the electric motor, as well as a cooling device which cools the field windings and the circuit breakers by its coolant circuit. The electric motor is realized in the form of a first modular unit which is mechanically functional in itself. The circuit breakers are assembled in at least one second modular unit, which is connected firmly to the first modular unit to form a propulsion unit. The individual modular units can be separated from one another and are connected to one another both by detachable electrical interface connections and also by detachable coolant interface connections. This construction makes it possible to selectively expand the propulsion unit by adding additional modular units, or in the event of the failure or malfunction of individual modular units to replace the modular units without having to replace the entire propulsion unit.
PCT Publication WO/1992/018346 discloses a hybrid electric vehicle propulsion system having an external combustion free-piston engine is provided with an integral linear electric current generator and a pulse frequency controller. The system includes a power integration processor, a frequency modulator circuit and a pulse width modulator circuit, the power integration processor controls the frequency modulator circuit and the pulse width modulator circuit to produce both a frequency modulated pulsed current and an auxiliary power current which varies in pulse width. Both the frequency modulated pulsed current and the pulse width modulated auxiliary current are combined to power an electric drive motor having an integral electronic differential. A small auxiliary power source, such as a rechargeable battery pack, provides the auxiliary current for acceleration and hill climbing power. The external combustion engine may burn any pollution free fuel (such as natural gas, alcohol, propane, etc.) and runs at a constant peak efficiency speed to generate constant frequency electric current from coils integrated into the engine. The generator current is sufficient to propel the vehicle in ordinary driving situations with smooth speed control of the drive motor. The propulsion motor combines one fixed stator, and two axially opposed permanent magnet or induction-type rotors, one for each output propulsion shaft.
U.S. Pat. No. 5,172,784 discloses a hybrid electric vehicle propulsion system having an external combustion free-piston engine is provided with an integral linear electric current generator and a pulse frequency controller. The system includes a power integration processor, a frequency modulator circuit and a pulse width modulator circuit, the power integration processor controls the frequency modulator circuit and the pulse width modulator circuit to produce both a frequency modulated pulsed current and an auxiliary power current which varies in pulse width. Both the frequency modulated pulsed current and the pulse width modulated auxiliary current are combined to power an electric drive motor having an integral electronic differential.
United States Patent Application 20060000651 discloses a thermoelectric augmented hybrid electric propulsion system for a hybrid electric vehicle is disclosed. The system includes a combustion engine and an electric motor for rotating wheels of the vehicle. A thermoelectric device having a hot side provided in thermal contact with the combustion engine is electrically connected to the electric motor. In operation, the thermoelectric device receives waste heat from the combustion engine and generates electrical power for the electric motor to augment the vehicle propulsion.
U.S. Pat. No. 6,823,840 discloses manifold absolute pressure control system and method for a hybrid electric vehicle. It discloses methods and apparatus are provided for controlling manifold absolute pressure in a hybrid electric vehicle that includes an internal combustion engine in parallel with an electric motor/generator. The method includes the steps of monitoring the torque demand on the hybrid electric vehicle, monitoring the manifold absolute pressure magnitude and change rate of the internal combustion engine, supplying torque from the internal combustion engine to meet the torque demand; and supplying torque from the motor/generator to load-level the torque supplied from the internal combustion engine and to maintain the manifold absolute pressure of the internal combustion engine within an acceptable range and rate.
United States Patent Application 20040174124 discloses motor control method and system for parallel hybrid electric vehicle. A motor control system is provided which control a motor using an acceleration command and an estimated inertia moment of a motor. The motor control method comprises of calculating an estimated inertia moment of a motor, calculating a forward compensation current based on the estimated inertia moment and an acceleration command, calculating a final current command based on a speed controller output current and the forward compensation current, the speed controller output current being calculated based on the acceleration command, and controlling the motor using the final current command.
United States Patent Application 20030098187 discloses a control system and method for a parallel hybrid electric vehicle. It provides a control strategy for a parallel hybrid electric vehicle (HEV) configuration where power from the engine and the motor can each independently provide torque to the vehicle power train.
U.S. Pat. No. 6,321,143 discloses control system and method for a hybrid electric vehicle. The vehicle system controller has a state machine having a plurality of predefined states that represent operating modes for the vehicle. A set of rules is defined for controlling the transition between any two states in the state machine. The states are prioritized according to driver demands, energy management concerns and system fault occurrences. The vehicle system controller controls the transitions from a lower priority state to a higher priority state based on the set of rules.
Japanese Patent JP3580257 discloses a hybrid car wherein at least one part of a transmission line for transmitting power of a plurality of driving power sources to a wheel is made common, and also a power transmission state control device for changing the power transmission state is provided between the two rotational members in the line where the power outputted from the specified driving power source in the plurality of driving power sources is transmitted to the wheel.
Japanese Patent JP2002135910 discloses hybrid vehicle and method for controlling the same. The power outputting unit is provided with a prime mover having an outputting shaft, a driving shaft outputting a power, a power adjusting unit which is coupled with the output shaft and the driving shaft and capable of transmitting to the driving shaft a power outputted from the prime mover, and increased or decreased, a motor having a rotating shaft, a change-over structure which switches a connection status of the rotating shaft, the outputting shaft and the driving shaft, and a change-over control unit controlling the change-over structure.
Japanese Patent JP3817982 discloses hybrid vehicle to improve power transmission efficiency of a continuously variable transmission in a hybrid vehicle.
Torque of an engine is transmitted to wheels through a continuously variable transmission and that torque of a motor generator can be inputted into a torque transmission path between the engine and the wheels, gears adding torque of the motor generator through a planetary gear mechanism.
U.S. Pat. No. 6,155,364 discloses hybrid drive system wherein planetary gear mechanism is disposed radially inwardly of stator coil of motor/generator. It includes (a) an engine operated by combustion of a fuel, (b) a planetary gear mechanism having a sun gear and a carrier one of which is connected to the engine, and a ring gear connected to an output member, (c) a motor/generator connected to the output member, and (d) a differential gear device including output shafts and an input member rotated by a drive force received from the output member, and wherein the motor/generator, the planetary gear mechanism and the output member are arranged coaxially with each other along a first axis, and the output shafts of the differential gear device are disposed along a second axis parallel to the first axis.
The critical review of the above mentioned patents reveal following technology gaps:                Non-availability of electrical drive systems that are adaptable on vehicles without subjecting major changes to the Engine/vehicle/their production line;        Non-adaptable motors for existing engines, in particular situations in which a motor with the same frame size is to be used for range of engine capacities thereby compelling manufacturers to develop dedicated engines integrated with specific motors and power transmission systems;        Non-adaptable control systems that seamlessly interface with engine/vehicle sensors and other control units;        Non-availability of rapid battery charging means.        Need of cooling systems for battery, motor etc.        
There is a long-felt need to provide a modular power assisting system, in particular electric power assisting system that is adaptable to a vehicle/engine driven system such that the vehicle/engine driven system can be operated/powered by electric system and its original power system.